Donnie and Sharon Leutjen and their 15-year-old granddaughter, Taron Leutjen, were found June 9. They had been shot to death, and their bodies had lain in their home in Cole Camp, Mo., for about two days.

Authorities know approximately when the Leutjens were shot because they got a 911 call on the night of June 7.

On the tape of the call — which investigators examined after the worried inquiries of someone who knew the family led to the bodies' discovery— “one of the male voices was directing Sharon Leutjen to sit down (and) put her arms behind her,” the sheriff’s office in Benton County, in central Missouri, said in court documents.

“At least two threats to shoot her and the other two victims” could be heard, the sheriff’s office said.

So why didn’t deputies rush to the scene as soon as they got the call?

They couldn’t. They didn’t know where it came from. Whoever made the call used a cell phone, and Benton County’s technology isn’t advanced enough to take advantage of location services that are standard features of nearly all cell phones sold today.

Benton County isn’t an isolated example. Cell phones may lure us with the promise of immediate help in an emergency, but depending on where you live, that promise can go unkept because of inadequate technology at one or both ends of a 911 call.

“Access to 911 from cell phones is very different from wired phones and also varies greatly around the country,” said the National Emergency Number Association, or NENA, the nonprofit industry group that works with governments to promote and institute 911 programs across North America.

In places that haven’t upgraded their 911 centers to the latest technology, “this presents life-threatening problems due to lost response time” if callers are unable to speak or don’t know where they are, the organization said.

That’s why emergency officials and wireless industry leaders say every household should have a centrally located, easily accessible land line for emergency calls. But increasingly, Americans are dropping their land lines and going wireless-only.

Some systems find only a cell tower
The problem is that, by definition, a mobile phone can be anywhere. It isn’t tied to an address, which automatically pops up on a 911 operator’s screen during a call from a land line.

Know your device911 can be contacted from nearly every device that can make phone calls, but callback and location information can vary drastically among technologies and between regions. It is your job to know the benefits and limitations of various technologies. Contact your service provider for more information.

Memorize important information
Being able to tell the 911 operator your address (your parents’ names if you are a child) and your phone number will get help faster. If you aren’t at home and don’t know the address where you are, look around for a street sign or a building with a name on it.

911 isn’t as cool as you are You can’t yet text or IM “9-1-1” to reach emergency services. That technology is in the testing phase, but for now you have to make an old-fashioned phone call if you want to talk to 911.

Adapted from “Making 911 Work for You,” a publication of the Association of Public Safety Communications Officials, CTIA/The Wireless Foundation and the National Emergency Number Association.

As cell phones have morphed into all-in-one multimedia toolboxes, U.S. carriers have integrated technology to use Global Positioning System satellites or their own towers to triangulate a phone’s location. It’s called Enhanced 911, or E911, and under Federal Communications Commission regulations, such capability must be built in to at least 95 percent of the phones a carrier sells.

But that information is only as good as the 911 infrastructure.

A decade after the Wireless Communications and Public Safety Act was enacted in 1999, requiring cell phone carriers to provide a caller’s location to 911, about 10 percent of the nation’s more than 6,000 call centers haven’t installed the equipment to use the information, NENA found in February. Those jurisdictions still offer only 1990s-vintage basic 911, which rely on callers’ knowing where they are and being able to communicate that.

“On cell phones, we do not have an exact location,” said Ken White, operations manager of the 911 center in Tulsa, Okla., which has asked for state help to pay for an E911 upgrade that will show a cell phone’s location and call-back number. Such information often isn’t now available, even though a little more than half of Tulsa’s 911 calls come in from cell phones, about the same proportion as they do nationwide.

E911 doesn’t solve all problems
Meanwhile, the 90 percent of systems that do relay a phone’s position don’t ensure that emergency crews will be able to find the caller.

For one thing, the accuracy of location data generally drops in rural areas, where older, less-advanced cell towers can be farther apart, the Congressional Research Service found in a background report for lawmakers late last year. And it can drop in densely populated cities, where a phone might show up as being at 1 Main St., with no indication of whether it’s on the seventh or the 77th floor.

Depending on the technology a carrier is using — GPS or tower triangulation — FCC regulations allow a margin of error of up to 300 meters for some E911-capable phones. That’s longer than three football fields.

The FCC also leaves it up to carriers to determine whether they’re complying with the E911 mandate. One way they can do that, it says, is “to prevent reactivation of older handsets” — in other words, when your contract runs out, the carrier can insist that you pay for a newer phone if you want to keep your service.

Analog system outdated in digital world
But the biggest obstacle is the underlying architecture of the 911 system itself.

The nonprofit 911 Industry Alliance found last year that most 911 systems still rely on older analog hardware. Even digital E911 operations are usually built — “or, perhaps more accurately, ‘jury-rigged’” — on analog platforms that reflect “the legacy telephone technology of the time the system was first designed,” it said.

That would be the late 1960s, when 911 service was optional and ran on circuits run by a single local land line provider. Today, call centers operate under scores of different local and state regulations that must accommodate not only land lines and traditional wireless phones, but also pre-paid mobile phones and Internet devices, all offered by dozens of deregulated carriers.

The result, the alliance said, is a fragmented system that leaves “many wireless callers without the benefits of location identification information when they call 911.”

That means a land line is still your best option in an emergency, NENA and AT&T said last week in launching a campaign urging Americans to keep some form of wired service for making emergency calls.

“The more choices you have to reach 911 in an emergency, the better, and a corded land line phone should be one of those options,” said Brian Fontes, chief executive of NENA.

More Americans dropping land lines
Americans, however, are increasingly disregarding that message.

Since 2003, the Centers for Disease Control and Prevention has asked Americans about their cell phone service when it conducts its twice-yearly National Health Interview Survey. The number of U.S. households that have ditched their land lines completely has risen consistently.

For the first time, wireless-only households hit 20 percent during the second half of last year, the CDC said, compared with 3.5 percent in 2003. Those households include nearly 19 percent of all children in the United States, the CDC found.

And when one of those families has to call 911, “they are apt to be disappointed — and left in the lurch,” the 911 Industry Alliance concluded.

“Consumers are often unaware of the limitations of 911 service in various geographic areas or with respect to certain technologies,” the alliance said, something it said should be “a grave source of concern for policymakers and industry professionals.”

NBC stations KJRH of Tulsa, Okla., and KYTV of Springfield, Mo., contributed to this report.

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